Improved marine propeller



UNITED STATES PATENT Einen.-

IMPROVED MARINE PROPELLER.

Specification forming part of Letters Patent No. 35,115] dated June 3,1862.

To @ZZ whom it may concern:

Be it known that I, WILLIAM H. JOHNSON, of Springfield, in the county ofHampden and State of Massachusetts, have invented an Im` provedPropeller for Vessels, of which the following is a full, clear, andexact description, reference being had to the accompanying drawings,making part of this specification, in Which- Figure 1 is a perspectiveView of a vessel with my improved propellers attached; Fig. 2, a plan ofthe propellers and-after part of the vessel, and a diagram showing thepath of the blades through the water when the vessel is being propelled;Fig. 3, detail to be referred to.

.t peller; but the action of the pivoted blade is entirely different. Inthe latter case the elastic blade, in itsattempt to follow the sinuouspath described by its pivot, as the arm'is vibrated at the same time thevessel is advancing, has a considerable proportion of its surfaceconstantly reacting against the body of water behind it, thus tending todrive the vessel ahead `with the greater part of the power used tovibrate the arm to which the blade is connected.

That others skilled in the art may understand and use my invention, Iwill proceed to describe the 'manner in which I have carried out thesame.

In the said drawings, A represents the hull of a steam-vessel. `For thepurpose of illustrating the movement of the propeller, I have placed inthe vessel a coiled spring, a, which is wound up by a crank, B, whichspring, when released,revolves a cog-wheel, C, which engages With apinion, D, on a vertical shaft, b, supported in suitable bearings. Aconnecting-rod, E, is pivoted at c eccentrically to the face of thepinion D. The other end of this rod E is pivoted at d to a cross-head,F,which A slides on suitable ways, e, attached to the vessel. 'Io eachend of this cross-head is pivoted a rod, f. I will here ystate that Ihave represented two of my propellers applied to this vessel, and that Iprefer to use them in pairs, vibrating in opposite directions, as onecounteracts and balances the other and prevents the oscillating motionwhich a single one would communicate to the vessel. A vertical shaft, i,placed immediately abaft the stern-post G, rests on a step, g,projecting aft from the keel. To this shaft is attached, by means of acollar, 5, and pin, at a short distance above the step, a rigid forkedarm, H, and to the upper end of this shaft, above where it passes upthrough the stern of the vessel, is attached an arm, I, to the outer endof which is pivoted one of the rods f. A sleeve, m, to which is attachedanother rigid forked arm, K, embraces the shaft z' above the collar 5.It has attached to its upper end, innmediately beneath the arm I, asimilar arm, L, to the outer end of which is pivoted the other rod f.'Ihus as the crosshead F is moved back and forth on its ways the twoforked arms H and K are vibrated horizontally in opposite directions.The edges of these arms should be made thin, to oier as littleresistance as possible in passing through the water.

As the propellers are similar, I need describe but one of them. The armH has its fork or legs l and 2 curved gradually outward and brought to apoint at the extreme end. Between these ends and at the crotch of thefork is pivoted to the arm H on avertical pivot, 6, an elastic blade,-M, which is free to vibrate horizontally between the legs l and 2 of thefork. The blade M here shown is made of sheet-brass stiffened along themiddle of its length and at the end which is pivoted by additionallayers or scales. Other metals may be used-such as galvanized steel-andother modes of constructing the blade may .be adopted, the object beingto have the blade as flexible and elastic as is consistent with thestrength required by its dimensions, the size of the blade as Well asthe length of the arm `I I'being apportioned to the size of the vesseland power of the engine.

'Ihe legs 1 and 2 or fork may in some cases be dispensed with; but Iprefer to use them, as

they carry the blade M through a greater lateral sweep than it wouldotherwise take.

When the engine is not in operation, the propeller or propellers mayoccupy a position in the axis of the vessel, as shown in Fig. 3, andoffer but little obstruction to her passage through the Water, in thisrespect being Well adapted to use as an auxiliary power tosailing-vessels.

The motions of this propeller will be understood from the diagram inFig. 2. The red line x represents, approximately, the path of the pivot6 and the front end of the blade M. This will of course vary with therelative rapidity with which the rigid arm H is vibrated and the speedof the vessel through the water. The dotted line y shows, approximately,the pat-h which would be described by the extreme end ofthe blade if itwere only slightly flexible and were carried around by the legs 1 and 2of the fork; but the more flexible the blade is made throughout itslength the more nearly will its path approach to that of its pivot 6,which it endeavors to follow. This sinuosity of the blade M enables itto present at all times some portion and during the greater part of itssweep a large proportioi/` effective propelling-surface to the water.'

Vhat I claim as my invention, and desire to secure by Letters Patent,is-

A propeller for vessels, consisting of a rigid vibratingv arm, H, towhich is pivoted an elastic blade, M, substantially as specified.

VILLIAM H. JOHNSON.

lVitnesses:

Tiros. R. Roxen, P. E. TEsoHEMAcHER.

